Draft gear



Dec. 16, 924 11 mm E. G. GOODWIN DRAFT GEAR Filed Oct. 25. 1921 5Sheets-Sheet 1 Dec. 1 1924.

E. a. oonwm DRAFT GEAR 5 Sheets-Sheet 2 Filed Oct. 25, 1921 Inf/766'sDec. 16, 4- I 1,519,831

E. G. GOODWIN DRAFT GEAR Filed Oct. 25, 1921 5 Sheets-Sheet 5 4 E. G.GOODWIN DRAFT GEAR Filed 001. 25. 1921 s Sheets-Sheet a.

Deac 16, 5924.

E. G. GOODWIN DRAFT GEAR Filed Oct. 25. 1921 5 Sheets-Sheet 5 WW vPatented Dec. 1%, 1924,

TES

ERNEST G. GOODWIN, OF NEW YORK, N. Y., ASSIGNOR T0 STANDARD COUPLER COM-PANY, OF NEVV YORK, N. Y., A, CORIE'QB-ATIQN OF NEW JERSEY.

DRAFT GEAR.

Application filed October 25, 1921. Serial No. 510,272.

T 0 all whom it may concern:

Be it known that I, ERNEST G. Goonwm' a citizen of the United States,residing at New York, in the county of New York and State of New York,have invented certain new and useful Improvements in Draft Gears; and Ido hereby declare the following to be a full, clear, and exactdescription of the same, reference being had to the accompanyingdrawings forming part of this specification.

This invention relates to shock absorbing devices and is shown in oneparticular embodiment as a standard friction draft gear for use inconnection with railway rolling stock. It will be readily apparent,however, that the various details forming parts of the invention may beused in other connections as for example in car truck shock absorbers,automobile truck bumpers, etc.

The object of the present invention is to improve various details ofdevices of the character stated so that a complete whole may be hadwhich shall be serviceable under all conditions.

In the drawings,

Figure 1 is a vertical central longitudinal section through the devicewith the parts in open position.

Fig. 2 is a similar view but with the parts in closed position.

Fig. 3 is a vertical section on line 3- of Figure 1. v

Fig. 1 is an end view of one of the barrels looking from the smaller endof the barrel.

Fig. 5 is an end view of the screw.

Fig. 6 is a fragmentary section taken on line 66 of Fig. 4:.

Fig. 7 is a section taken on line 77 of Fig. 1.

Fig. 8 is a view taken on line 8-8 of Fig. 5.

Fig. 9 is a view taken on line 99 of: Fig. 5.

Figs. 10 and 11 show modifications.

The friction draft gear illustrated as showing an embodiment of myinvention consists of a pair of similar barrels each having a head. 10and a cylindrical portion 11, the cylindrical portion of one of thebarrels being grooved as at 12 to receive the right hand threads 13 ofthe screw member and the cylindrical portion 11 of the other barrelbeing grooved as at it to receive the left hand threads 15 of the screw.The heads or end plates of each of the barrel members are connected tothe cylindrical portion of the barrel by means of short verticalstifiening ribs 17 and by four diagonal stiifening ribs or flanges 19.

The screw is a single cylindrical piece of metal having a partition 22at its middle point in which is formed a central hole 23 for the passageof a through-bolt when one is employed. This hole may be of the samediameter as the inner diameter of the coiled springs 25 and 26. Theinner ends of the springs abut against shoulders or seats 27 formed onthe partition, on opposite sides as shown in full and dotted lines inFig. 5. The outer or opposite end of the spring 25 seats against ashoulder or seat 28 in the barrel and the corresponding end of thespring 26 against a similar seat, not shown in the drawings, but exactlysimilar to the seat 28.

Each of the seats for the springs is made parallel with the ends 29 ofthe springs, these spring ends being preferably in a plane at rightangles, that is, normal. to a central helical line through the metal ofthe spring: in other words, the end faces of the spring are normal tothe axis of the bar from which the spring is made before it is woundinto the helical sh ape shown. In the making of ordinary draft gears ofthis type the spring must be flattened or have otherwise a finished end.whereas. in the form shown in the drawings the spring may be woundwithout regard to its end and may be later cut off into predeterminedlengths with ends bearing the correct relation to one another. The seatsor stops 27 and 28. would. in the usual course of manufacture. be castin both the gear ends and in the central screw piece and may either bein the form of a continuous spiral with the end of the spiral forming astop, or, to lighten the structure, portions of the spiral may beomitted. leaving separated proiections 27 28 on which the finalconvolution of the spring rests when fully compressed or driven upsolid.

Particular attention is called to the fact that each of the springs isso made that the spring will unwind as the gear is closed under load,this being a novel feature, all other gears winding the springs as thegears are closed. This, while universal, is disadvantageous in that thespring has to be annealed after winding in order to form the properlyshaped ends. Attention is also called to the important feature that thespring is non-circular in cross section. By using a bar of square orrectangular cross section rather than a circular bar it is posble toincrease the spring capacity with the same thickness of bar wound on acore of the same diameter by nearly three-quarters. I find it preferablein order to secure a high capacity gear to form the spring of a bar ofrectangular section wound on edge as shown in the drawings.

The usual square screw thread has been eliminated in this type and thesloping face threads 13 and 15 substituted. By sloping the threads asshown in the various figru'es the manufacture of the barrels and of thescrew, both of which are of cast metal, is much simplified as thetapered thread. aids in the drawing of the patterns, this apply ing toboth faces of the threads. It will be readily understood that I may formeither the working face of the thread or the rear face square thussecuring part of the advantage, but not all. A second advantage and onewhich was found to be of greater importance than the simplicity ofmanufacture is the ability to change or increase the capacity of thegear and also secure uniform regularity or smoothness of action bychanging the slope on the working face of the threads. Obviously thegreater the pitch or lead of the screw the smaller the angular movementas the heads approach each other and in order to maintain the capacitythe slope of the working face of the threads is designed to give thedesired increased friction due to the wedging action. From the above itis clear that the capacity of the gear may be changed by changing thepitch or lead or by changing the slope or incline of the working face ofthe threads or both.

As will be seen from Fig. 3 six threads are cast on the screw, thisnumber of course being arbitrary. Five of these threads are of the samesize, but the other, a master thread 33, is wider than the other five soas to prevent an incorrect assembly of the device. Each of the heads hasa single master thread and the screw has a corresponding groove 34 whichmay be seen at the left hand side of Fig. 5. In view of the number ofthreads it would be very easv to assemble the gear incorrectly if eachwere of the same cross section so that when closed the end plates wouldnot be in the same parallel planelongitudinally of the gear or in casethe heads were forced into the same plane one end of the gear would beclosed before the opposite end. By providing a master thread, such asshown at 33', the gear can only be assembled in one way,'this masterthread being so located. that when the end pieces are screwed on theywill both come to the transverse center line of the gear and at suchtime will be in the same plane. While there are numerous other ways ofpreventing incorrect assembly the arrangement shown :has been foundparticularly useful and advantageous in that it takes no capacity fromthe gear, is no more expensive to manufacture than equal size threads,and always prevents incorrect sembly of the gear even after the partsare very much worn.

In order to provide means for the escape of dust, water, or grit thatmay tend to collect in the gear and hinder its action, a number of holessuch as 35 are provided, these holes being so located that whether thegear is used vertically or horizontally one of the holes 35 will be atthe bottom. The holes are therefore preferably substantially 90 apart ineach head.

Referring now particularly to Figs. 3 and 5, the screw is shown split asat 36 forming a plurality of tongues 3'? here shown as five in numbereach of the splits extending from each end back toward the mid-portionof the Screw. Since the springs 25 and 26 in the preferred formillustrated in the drawings, Figs. 1 to 9, are flat'on their peripheriesand hence afford a great amount of bearing for the encircling memberhere shown as the screw, it is possible to materially increase thecapacity of the gear by forming these tongues so that each of them willbe forced inward by the sloping work ing face of the thread and therebycaused to frictionally grip the outer surface of the springs as the gearis compressed. As the gear is released these segments or tongues,although of cast metal, will be sufficiently resilient to return tonormal and offer no obstruction to the return of the spring to openposition.

Referring now particularly toQFigs. 5, 8 and 9, the central partition 22of the screw is provided with projections 40 and 40 of a lengthsubstantially equal to the longitudinal thickness of the springs 25 and26, each of which is provided with a hole 42 or 42' to receive the pin40 when the spring is in its correct position. This feature incombination with the master thread which prevents incorrect assembly ofthe screw and heads prevents incorrect assembly of the spring and thescrew and thereforethe combination of the master thread and the pinsabsolutely prevents incorrect assembly of the gear. It will'be readilyunderstood that a pin, similar to 40, may be provided on the spring inwhich case such pin would fit into a hole or socket in the partitionwall 22 of the screw. The spring seats forming part of the centralpartition in the screw form thick or heavy sections of metal and theseare conveniently utilized for the formation of radial sockets 44 shownin dotted lines, Fig. 5, and in the detail section, Fig. The holes atare not essential, but have been found to be of great convenience inreceiving the end of a bar or similar implement by means of which thescrew may be turned by hand to draw the heads toward each other in theinitial or emergency as sembling of the parts.

The gears are usually assembled at the factory and are shipped undeinitial compression to standard dimensions reac y for application to thecar and for this purpose each head is provided with an internal bossithaving an external socket l? and perfo rated as at 48 to receive thetie rod 49. The head 50 of the rod is received in the socket l of onehead, while the socket l? of the cooperatinghead receives the threadedend. 51 of the bolt 4E9 carrying a nut 52.

By reference to Figs. 1, 2, l and 5, it will be seen that looking orsticking of the threads, such for example as might be caused by the endsof the threads wedging together when the gear is set up solid, isprevented by cutting away or reducing a portion of such ends.Conveniently the meetings ends of the external threads are cut away forone-half their height as at 56 (Figs. 1 and 5) and the internal threadsfor one-half their height as at 57 (1, 2 and 4-). By this constructionall danger of the threads becoming jammed or locked together is avoidedeven though one head should advance to the limit of its movement beforethe other.

By employing right and left hand threads respectively in opposite endsof the gear and spring end abutments facing clockwise at the center and(JOUHtQY-ClOCliWlSQ at the ends (or the reverse) and locating the centerabutments or seats 180 apart a very perfectly balanced gear is producedwith the employment of a minimum weight of metal and a maximum springspace. The location of the center seats 180 apart permits the ends ofthe springs to overlap giving greater spring space at each end of thegear.

The sloping or inclined faces of the screw threads make it possible todesign the gear so as to increase the capacity without increasing thestrength of the spring or to use a spring of less strength withoutdecreasing the capacity of the gear all by designing the slope of thethread faces to give the desired results.

l vhile the gear thus far described is that preferred the major featuresof the invention may be readily incorporated in gears, bnfiing or shockabsorbing mechanism in which the relation of the parts is reversed, thatis to say, the spring may be located either inside or outside and thecentral screw and heads or barrels may have either internal or externalscrew threads. Modifications of this character are shown in Figs. 10 and11.

T Fig. if) the screw 60 has internal hreads while the heads 61 haveexternal tl reads, while the springs 62 are located on the exterior. InFig. 11 the same arrangement of the screw and heads is preserved, butthe springs (53 are located in the interior of the gear. The details ofconstruction other than above noted may conform to the details of theconstruction first described, the spring seats, of course, beingarranged to suit the location of the springs.

In all -ases it is preferred to impart an caitwardly bendii'ig movementto the springs by reason of the relative angular movement of the partsin closing, the torsional movement being imparted by the reduction inthe length or closing of the coils of the springs, lloth of these forcesare utilized to resist butting strains but it will be noted that the useof springs of rectangular section with the greater dimension in theplane of the bending movement permits of a greatly increased capacitywithout requiring proportionally large springs or spring pace and hencea high capacity gear may be provided well within the dimensionspermissible in railway car practice. It also makes it practicable toconstruct shock absorbing devices of small size for use in practicallyany apparatus where such devices are desirable.

The frictional resistance due to the form and operation of the screwthread not only acts to increase the capacity of the gear on compressionbut it also operates to control the recoil sutliciently to preventinjurious effects but at the same time the return to normal is promptand effective to restore the controlled. parts to normal position.

l t hat is claimed is:

1. In a pressure resisting gear, pair of relatively rotatable threadedmembers, a spring having a hole therein and adapted to hold said membersin operative position, a lug on one of said members adapted to extendinto said hole whereby improper as sembly of the device is prevented.

2. In a pressure resisting gear, a barrel, a screw coaxial with saidbarrel, and aspring located between said screw and said barrel andengaging each of said members, said screw being split to form aplurality of yielding segments.

3. In a pressure resisting gear, an internally threaded barrel, anexternally threaded screw fitting therein and movable longitudinallythereof, a spring engaging saic. screw and said barrel, said screw beingsplit to form a plurality of resilient tongues, thereby increasing thefriction by the deflection of said tongues against the surface of saidSPI'IIIO'.

4. In a pressure resisting gear, a plurality of internally threadedopposing barrel members, a right and left handed screw litting withinboth of said barrel members, a spring having a hole therein and adaptedto hold one of said barrels and said screw separated from one another, alug carried by said screw and adapted to extend into the hole in saidspring whereby improper assembly of said spring may be detected.

5. In a pressure resisting gear, a hollow threaded screw having acentral partitioi'i, said screw being split on either side of saidpartition to form a plurality of segments, a spring within said screwnormally out of contact therewith, and means for bending said segmentsagainst said spring.

6. In a pressure resisting gear, a plurality of internally threadedbarrels, a right and left hand screw having beveled threads and fittingwithin each of said barrels, a central partition within said screw,aspring on either side of said partition and loosely fitting within saidscrew and adapted to hold the adjacent barrel member spaced from saidpartition, said screw being split on either side of said partition toform tongues whereby when said barrel members are forced together saidtongues will engage the outer surfaces of said springs therebyincreasing the friction of the gear.

7 In a pressure resisting gear, the combination. with oppositelydisposed head mem bers having cylindrical extensions, an inter-- mediatescrew having right and left hand screw threaded engagement with saidcylindrical ex ensions respectively to telescope therewith, springabutments on the head members facing in the same direction, springabut-ments on the screw facing in'the same direction and opposite to thedirection in which the abutments on the head members face, of coilsprings cooperating with said abutments interposed between said partsfor holding them in extended relation and both operating to resistrotation of the screw in one direction, and a through-bolt for limitingthe movement of said head members away from each other.

8. A pressure resisting gear having telescoping members with multiplescrew threaded engaging surfaces, and a spring for holding said membersextended, one of the screw threads and its cooperating groove being ofgreater cross sectional area than the others whereby incorrect assemblyis prevented.

9. A pressure resisting gear having head members and an intermediatemember telescoping together with multiple screw threaded engagingsurfaces, a spring holding said members apart,-one of said screw threadsand its cooperating groove at each end of the intermediate members beingof greater cross sectional area than the others to prevent incorrectassembly.

10. In a pressure resisting gear, the combination ofhead members havingcylindrical extensions, with internal right and left hand multiple screwthreads, an intermediate screw member having external right and lefthand multiple screw threads telescoping into the head members, one ofsaid screw threads of each member being a master thread to preventincorrect assembly, and right and left hand coil springs both operatingto turn the screw member in the same direction.

11. In a pressure resisting gear, the combination with oppositelydisposed head members, of an intermediate member telescoping therewithand having a central partition with plane spring engaging seats thereonlocated on opposite sides of the centre and facing in the same angulardirection whereby said seats may be brought more nearly into the sametransverse plane, and right and left hand coil springs engaging saidseats for resisting compression of the members.

12. A pressure resisting gear having cooperating screw threadedtelescoping members of right and left hand pitch, and right and lefthand coil springs cooperating with abutment; seats on said members, saidsprings having recesses therein and said abutments having projectionsthereon, and members in. different relation to the right and left handspring seats and ends of the springs whereby the location of the springsin incorrect relation is prevented.

ERNEST G. GOODWIN.

